OALGen detected that the file '\\SVR-SAMC\ExchangeOAB\8251f7db-4cda-44a0-84bb-2e1baa317bc8\6d0289ec-39a5-4325-a81f-0227b21f8e3b-data-10.lzx' is corrupted or missing. This indicates data tampering or disk problems. Restore files in this folder from the recent backup or clean up folder content and force a full OAB generation.
- Default Offline Address Book

I created a new OAB and set it as default but this had no impact on the error. This error has been present for a long time and the customer has complained about a missing shared address book (new customer so I am fuzzy on details of their complaint).

Any ideas how to proceed with solving this problem? Exchange has been fully patched and has all service packs installed.